FIG. 2.

(a) Restriction map of the vectors pSM02 and pSM03. Boxed arrows represent the genes; the light gray arrow represents orf18, the dark gray arrow represents corA, and the black arrow represents ltnI. The thick gray line represents the vector pNZ8048. The nisin-inducible promoter is shown as a black arrow. (b) Selection plates after transformation of competent L. lactis NZ9800 with pSM02 and pSM03 plated onto 5 μg of chloramphenicol/ml and 2.5 mM CoCl₂ after incubation overnight at 30°C. (c) Well diffusion assays demonstrating immunity of NZ9800(pSM02) and NZ9800(pSM03) exhibited against lacticin 3147. Immunity in the absence of nisin is shown in the top panel and in the presence of nisin is shown in the bottom panel.